Protein surface recognition via chemically enhanced phage display

Abstract

Low molecular weight molecules able to penetrate cells and tissues and having high specificity and affinity for the surfaces of proteins. Methods of making same, pharmaceutical compositions comprising same, and methods of treating cancers, infectious diseases, and diseases and disorders associated with aberrant protein expression using same. A method for selecting a therapeutic peptide for binding to an isolated and/or purified protein of interest by screening a phage display library containing phage particles with phage display peptides which have at least one APBA modified cysteine residue. The APBA modified cysteine residues bind to surface lysine residues on the isolated and/or purified protein of interest by dynamic covalent conjugation to form iminoboronates.

What is claimed is: 
     
       1. A drug screening method for selection of a therapeutic peptide for binding a protein of interest, the method comprising:
 screening a phage display library comprising phage particles comprising phage display peptides comprising at least one acetylphenylboronic acid (APBA) modified cysteine residue, wherein the APBA modified cysteine residue binds to an isolated and/or purified form of the protein of interest; and 
 selecting peptide binders with submicromolar affinity against the isolated and/or purified form of the protein of interest; 
 wherein the selected peptide binders are inhibitors targeting the protein of interest. 
 
     
     
       2. The method of  claim 1 , wherein the phage display peptides comprise two APBA modified cysteine residues. 
     
     
       3. The method of  claim 1 , wherein the phage display peptides comprise a peptide sequence given by:
   XC*(X) n C*(X) m , 
 wherein C* represents an APBA modified cysteine residue; wherein each instance of X is independently selected from A, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, and Y. 
 
     
     
       4. The method of  claim 1 , wherein the at least one APBA modified cysteine residue has a structure given by a formula: 
       
         
           
           
               
               
           
         
       
       wherein each of A 1  and A 2  are independently C1-C6 alkyl and the asterisks signify additional portions of the peptide or attachment to the phage particle. 
     
     
       5. The method of  claim 4 , wherein the APBA modified cysteine residue has a structure given by a formula: 
       
         
           
           
               
               
           
         
       
     
     
       6. The method of  claim 1 , wherein the protein of interest is selected from the group consisting of a bacterial protein, a viral protein, a fungal protein, a misfolded protein, an overexpressed protein, a protein expressed by a cancer cell, or a combination thereof. 
     
     
       7. The drug screening method of  claim 1 , wherein the selected peptide binders are further conjugated with a therapeutic residue targeting the protein of interest.